Blow-by filter for internal combustion engines

ABSTRACT

An open-ended canister includes a blow-by intake port for receiving contaminated blow-by gases and a fuel vapor exhaust port for venting purified blow-by gases. The open end of the canister is fitted with a removable cover that can be clamped in place. The removable cover includes an oil drainage port for draining cleansed engine oil back to the crankcase of the engine. The canister contains a filtering assembly made of multiple layers of metal mesh of differing gauges. The metal mesh may include one type of metal or several types of metal.

FIELD OF THE INVENTION

The present invention generally relates to a filter for controllingpollution produced by an internal combustion engine. More particularly,the present invention relates to a filter for blow-by gases createdwithin the crankcase of an internal combustion engine.

BACKGROUND OF THE INVENTION

The basic operation of standard internal combustion engines varysomewhat based on the type of combustion process, the quantity ofcylinders and the desired use/functionality. For instance, in atraditional two-stroke engine, oil is pre-mixed with fuel and air beforeentry into the crankcase. The oil/fuel/air mixture is drawn into thecrankcase by a vacuum created by the piston during intake. The oil/fuelmixture provides lubrication for the cylinder walls, crankshaft andconnecting rode bearing in the crankcase. In a standard gasoline engine,the fuel is then compressed in the combustion chamber and ignited by aspark plug that causes the fuel to burn. There are no spark plugs in adiesel engine, so combustion in a diesel engine occurs only as a resultof the heat and compression in the combustion chamber. The piston isthen pushed downwardly and the exhaust fumes are allowed to exit thecylinder when the piston exposes the fuel vapor exhaust port. Themovement of the piston pressurizes the remaining oil/fuel in thecrankcase and allows additional fresh oil/fuel/air to rush into thecylinder, thereby simultaneously pushing the remaining exhaust out thefuel vapor exhaust port. Momentum drives the piston back into thecompression stroke as the process repeats itself.

Alternatively, in a four-stroke engine, oil lubrication of thecrankshaft and connecting rod bearing is separate from the fuel/airmixture. Here, the crankcase is filled mainly with air and oil. It isthe intake manifold that receives and mixes fuel and air from separatesources. The fuel/air mixture in the intake manifold is drawn into thecombustion chamber where it is ignited by the spark plugs (in a standardgasoline engine) and burned. In a diesel engine, the fuel/air mixture isignited by heat and pressure in the combustion chamber. The combustionchamber is largely sealed off from the crankcase by a set of pistonrings that are disposed around an outer diameter of the pistons withinthe piston cylinder. This keeps the oil in the crankcase rather thanallowing it to burn as part of the combustion stroke, as in a two-strokeengine. Unfortunately, the piston rings are unable to completely sealoff the piston cylinder. Consequently, crankcase oil intended tolubricate the cylinder is, instead, drawn into the combustion chamberand burned during the combustion process. Additionally, combustion wastegases comprising unburned fuel and exhaust gases in the cylindersimultaneously pass the piston rings and enter the crankcase. The wastegas entering the crankcase is commonly called “blow-by” or “blow-bygas”.

Blow-by gases mainly consist of contaminants such as hydrocarbons(unburned fuel), carbon dioxide or water vapor, all of which are harmfulto the engine crankcase. The quantity of blow-by gas in the crankcasecan be several times that of the concentration of hydrocarbons in theintake manifold. Simply venting these gases to the atmosphere increasesair pollution. Although trapping the blow-by gases in the crankcaseallows the contaminants to condense out of the air and accumulatetherein over time. Condensed contaminants form corrosive acids andsludge in the interior of the crankcase that dilutes the lubricatingoil. This decreases the ability of the oil to lubricate the cylinder andthe crankshaft. Degraded oil that fails to properly lubricate thecrankcase components (e.g. the crankshaft and connecting rods) can be afactor in poor engine performance. Inadequate crankcase lubricationcontributes to unnecessary wear on the piston rings which simultaneouslyreduces the quality of the seal between the combustion chamber and thecrankcase. As the engine ages, the gaps between the piston rings andcylinder walls increase resulting in larger quantities of blow-by gasesentering the crankcase. Too much blow-by gases entering the crankcasecan cause power loss and even engine failure. Moreover, condensed waterin the blow-by gases can cause engine parts to rust.

These issues are especially problematic in diesel engines. Dieselengines burn diesel fuel which is much more oily and heavy thangasoline. As it burns, diesel fuel produces carcinogens, particulatematter (soot), and NOx (nitrogen contaminants). This is why most dieselengines are associated with the image of a big rig truck belching blacksmog from its exhaust pipes. Similarly, the blow-by gas produced in thecrankcase of a diesel engine is much more oily and heavy than gasolineblow-by gas. Hence, crankcase ventilation systems for diesel engineswere developed to remedy the existence of blow-by gases in thecrankcase. In general, crankcase ventilation systems expel blow-by gasesout of a positive crankcase ventilation (PCV) valve and into the intakemanifold to be re-burned. In a diesel engine, the diesel blow-by gasesare much heavier and oilier than in a gasoline engine. As such, thediesel blow-by gases must be filtered before they can be recycledthrough the intake manifold.

PCV valves recirculate (i.e. vent) blow-by gases from the crankcase backinto the intake manifold to be burned again with a fresh supply ofair/fuel during combustion. This is particularly desirable as theharmful blow-by gases are not simply vented to the atmosphere. Acrankcase ventilation system should also be designed to limit, orideally eliminate, blow-by gas in the crankcase to keep the crankcase asclean as possible. Early PCV valve comprised simple one-way checkvalves. These PCV valves relied solely on pressure differentials betweenthe crankcase and intake manifold to function correctly. When a pistontravels downward during intake, the air pressure in the intake manifoldbecomes lower than the surrounding ambient atmosphere. This result iscommonly called “engine vacuum”. The vacuum draws air toward the intakemanifold. Accordingly, air is capable of being drawn from the crankcaseand into the intake manifold through a PCV valve that provides a conduittherebetween. The PCV valve basically opens a one-way path for blow-bygases to vent from the crankcase back into the intake manifold. In theevent the pressure difference changes (i.e. the pressure in the intakemanifold becomes relatively higher than the pressure in the crankcase),the PCV valve closes and prevents gases from exiting the intake manifoldand entering the crankcase. Hence, the PCV valve is a “positive”crankcase ventilation system, wherein gases are only allowed to flow inone direction—out from the crankcase and into the intake manifold. Theone-way check valve is basically an all-or-nothing valve. That is, thevalve is completely open during periods when the pressure in the intakemanifold is relatively less than the pressure in the crankcase.Alternatively, the valve is completely closed when the pressure in thecrankcase is relatively lower than the pressure in the intake manifold.One-way check valve-based PCV valves are unable to account for changesin the quantity of blow-by gases that exist in the crankcase at anygiven time. The quantity of blow-by gases in the crankcase varies underdifferent driving conditions and by engine make and model.

PCV valve designs have been improved over the basic one-way check valveand can better regulate the quantity of blow-by gases vented from thecrankcase to the intake manifold. One PCV valve design uses a spring toposition an internal restrictor, such as a cone or disk, relative to avent through which the blow-by gases flow from the crankcase to theintake manifold. The internal restrictor is positioned proximate to thevent at a distance proportionate to the level of engine vacuum relativeto spring tension. The purpose of the spring is to respond to vacuumpressure variations between the crankcase and intake manifold. Thisdesign is intended to improve on the all-or-nothing one-way check valve.For example, at idle, engine vacuum is high. The spring-biasedrestrictor is set to vent a large quantity of blow-by gases in view ofthe large pressure differential, even though the engine is producing arelatively small quantity of blow-by gases. The spring positions theinternal restrictor to substantially allow air flow from the crankcaseto the intake manifold. During acceleration, the engine vacuum decreasesdue to an increase in engine load. Consequently, the spring is able topush the internal restrictor back down to reduce the air flow from thecrankcase to the intake manifold, even though the engine is producingmore blow-by gases. Vacuum pressure then increases as the accelerationdecreases (i.e. engine load decreases) as the vehicle moves toward aconstant cruising speed. Again, the spring draws the internal restrictorback away from the vent to a position that substantially allows air flowfrom the crankcase to the intake manifold. In this situation, it isdesirable to increase air flow from the crankcase to the intakemanifold, based on the pressure differential, because the engine createsmore blow-by gases at cruising speeds due to higher engine RPMs. Hence,such an improved PCV valve that solely relies on engine vacuum and thespring-biased restrictor does not optimize the ventilation of blow-bygases from the crankcase to the intake manifold, especially insituations where the vehicle is constantly changing speeds (e.g. citydriving or stop-and-go highway traffic).

One key aspect of crankcase ventilation is that engine vacuum varies asa function of engine load, rather than engine speed, and the quantity ofblow-by gases varies, in part, as a function of engine speed, ratherthan engine load. For example, engine vacuum is higher when enginespeeds remain relatively constant (e.g. idling or driving at a constantvelocity). Thus, the amount of engine vacuum present when an engine isidling (perhaps 90° rotations per minute (rpm)) is essentially the sameas the amount of vacuum present when the engine is cruising at aconstant speed on a highway (for example between 2,500 to 2,800 rpm).The rate at which blow-by gases are produced is much higher at 2,500 rpmthan at 900 rpm. But, a spring-based PCV valve is unable to account forthe difference in blow-by gas production between 2,500 rpm and 900 rpmbecause the spring-based PCV valve experiences a similar pressuredifferential between the intake manifold and the crank case at thesedifferent engine speeds. The spring is only responsive to changes in airpressure, which is a function of engine load rather than engine speed.Engine load typically increases when accelerating or when climbing ahill, for example. As the vehicle accelerates blow-by gas productionincreases, but the engine vacuum decreases due to the increased engineload. Thus, the spring-based PCV valve may vent an inadequate quantityof blow-by gases from the crankcase during acceleration. This problem isfurther complicated when the PCV valve becomes gummed up withparticulate matter in the blow-by gas and is no longer capable ofopening and closing normally.

Regularly changing the lubricating oil in the crankcase can help keepthe PCV valve from seizing up with sludge, but even regular oil changesmay not help if the gasoline or diesel fuel used in the engine iscontaminated, thereby producing contaminated blow-by gasses. A pluggedPCV valve will eventually damage the engine.

Accordingly, there is a need for an extra filtration step to ensure theblow-by gas entering the PCV valve is relatively free of oil and othercontaminants. The present invention fulfills these needs and providesother related advantages.

SUMMARY OF THE INVENTION

The present invention comprises a blow-by filter for an internalcombustion engine. The blow-by filter includes a canister with a closedtop portion and an open bottom portion. The closed top portion includesa blow-by intake port and a fuel vapor exhaust port therein. The bottomportion includes a removable cover that is configured to cover the openbottom portion of the canister. The removable cover is fitted with anoil drainage port. The canister contains a filtering assembly. Thefiltering assembly is made from multiple layers of metal mesh ofdiffering gauges.

The multiple layers of metal mesh in the filtering assembly are made ofa type of metal including steel, stainless steel, aluminum, copper,brass, or bronze. The multiple layers of metal mesh of differing gaugesmay be all one type of metal, or may be a combination of two or moretypes of metal. The filtering assembly is contained in the canister bythe removable cover in the bottom portion of the canister. The removablecover is held in place with clamps between the open bottom portion ofthe canister and the removable cover. A gasket may be placed in betweenthe removable cover and the open bottom portion to provide an air-tightseal therein. The gasket may be made of a compressible material that isheat resistant and impermeable to both air and liquid.

Other features and advantages of the present invention will becomeapparent from the following more detailed description, taken inconjunction with the accompanying drawings which illustrate, by way ofexample, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate the invention. In such drawings:

FIG. 1 is a schematic illustration of a blow-by filter for a car engine;

FIG. 2 is a schematic illustration showing the general functionality ofthe blow-by filter with a PCV valve and a combustion-based car engine;

FIG. 3 is an elevational view of the blow-by filter, illustrating theplacement of the intake, exhaust, and oil drainage ports;

FIG. 4 is an enlarged side view of the area indicated by circle 4 ofFIG. 3, illustrating the closed top portion of the canister of theblow-by filter;

FIG. 5 is an enlarged fragmented view taken from circle 5 of FIG. 3,illustrating the bottom portion of the canister of the blow-by filter;

FIG. 6 is a cut-away side view of the blow-by filter, illustrating thefiltering assembly with its multiple layers of metal mesh of differinggauges; and

FIG. 7 is an exploded view of the bottom portion of the canister of theblow-by filter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in the drawings for purposes of illustration, a blow-by filterfor an internal combustion engine is referred to generally by thereference number 10. In FIG. 1, the blow-by filter 10 is preferablymounted under a hood 16 of an automobile 14, adjacent to an engine 12.The blow-by filter 10 is coupled to the engine 12 and receives blow-bygases from the engine 12. These gases are filtered by the blow-by filter10, and purified gasoline vapors are re-burned by the engine 12, whilepurified engine oil drains back into the engine 12. This process isdescribed in more detail below.

FIG. 2 is a schematic illustrating the operation of the blow-by filter10 in conjunction with a PCV valve 18 in a car engine 12. As shown inFIG. 2, the blow-by filter 10 and PCV valve 18 are disposed between thecrankcase 20, of an engine 12, and an intake manifold 22. In a dieselengine, the intake manifold 22 receives a mixture of fuel and air via afuel line 28 and an air line 24. The fuel line 28 also provides fuel fordirect injection into the combustion chamber 38. In a gasoline engine,the fuel line 28 does not directly inject fuel into the combustionchamber 38. Rather, the fuel line 28 is only connected to the intakemanifold 22. An air filter 26 may be disposed between the air line 24and the air intake line 32 to filter fresh air entering the intakemanifold 22. The air in the intake manifold 22 is delivered to a pistoncylinder 34 as a piston 36 descends downward within the cylinder 48 fromthe top dead center. As the piston 36 descends downward, a vacuum iscreated within a combustion chamber 38. Accordingly, an input camshaft40 rotating at half the speed of the crankshaft 42 is designed to openan input valve 44 thereby subjecting the intake manifold 22 to theengine vacuum. Thus, air is drawn into the combustion chamber 38 fromthe intake manifold 22.

Once the piston 36 is at the bottom of the piston cylinder 34, thevacuum effect ends and air is no longer drawn into the combustionchamber 38 from the intake manifold 22. At this point, the piston 36begins to move back up the piston cylinder 34, and the air in thecombustion chamber 38 becomes compressed. Next, in a diesel engine, fuelis injected directly into the combustion chamber 38 from the fuel line28. This injection is further aided by more compressed air from acompressed air line 30. The compressed air line 30 is not present in agasoline engine. As the air and fuel in the combustion chamber 38 iscompressed, it heats up until the fuel ignites and combustion occurs. Ina gasoline engine, a spark plug (not shown) replaces the fuel line 28and compressed air line 30 that feed into the combustion chamber 38. Thespark plug provides the ignition for the fuel, which then combusts. Thisis the main difference between diesel and gasoline engines. A gasolineengine relies on spark plugs to provide fuel ignition, while a dieselengine needs only heat and compression.

The rapid expansion of the ignited fuel/air in the combustion chamber 38causes depression of the piston 36 within the cylinder 34. Aftercombustion, an exhaust camshaft 46 opens an exhaust valve 48 to allowescape of the combustion gases from the combustion chamber 38 out anexhaust line 50. Typically, during the combustion cycle, excess exhaustgases slip by a pair of piston rings 52 mounted in a head 54 of thepiston 36. These “blow-by gases” enter the crankcase 20 as high pressureand temperature gases. Over time, harmful exhaust gases such ashydrocarbons, carbon monoxide, nitrous oxide and carbon dioxide cancondense out from a gaseous state and coat the interior of the crankcase20 and mix with the oil 56 that lubricates the mechanics within thecrankcase 20. The PCV valve 18 is designed to recycle these blow-bygases from the crankcase 20 to be re-burned by the engine 12. This isaccomplished by using the pressure differential between the crankcase 20and the intake manifold 22. In operation, the blow-by gases exit therelatively higher pressure crankcase 22 through a vent 58 and travelthrough a vent line 60, the blow-by filter 10, the PCV valve 18, andthen return to the engine via either the fuel line 28 or the blow-byline 62. The fuel line 28 receives fuel vapors that are more pure, whilethe less pure blow-by gases are vented from the crankcase 20 to theintake manifold 22 via the blow-by line 62. In a gasoline engine, theblow-by gases can only return via the blow-by line 62 as there is nodirect fuel injection. This process may be digitally regulated by amicro controller (not shown).

The PCV valve 18 regulates the vacuum between the intake manifold 22 andthe crankcase 20. The PCV valve 18 includes a one-way check valve (notshown) that opens to allow blow-by gases through the valve when thevacuum between the intake manifold 22 and the crankcase 20 is strongenough. With the one-way check valve open, blow-by gases pass throughthe PCV valve 18 to be recycled through the intake manifold 22. Once thevacuum pressure subsides, the one-way check valve closes preventing theblow-by gas from passing through the PCV valve 18. The one-way checkvalve can also be controlled by a micro controller for added fuelefficiency.

As stated above, blow-by gases are not pure fuel vapors. Rather, whenthe un-ignited fuel is pulled into the crankcase 20, past the pistonrings 52, the fuel vapors mix with the oil 56 that lubricates themechanics within the crankcase 20. Over time, harmful exhaust gases suchas hydrocarbons, carbon monoxide, nitrous oxide and carbon dioxide cancondense out from a gaseous state to mix with the oil 56 and the fuelvapors. Thus, the resulting blow-by gases contain harmful impuritiesmaking them unsuitable for re-burning in the engine. In a diesel engine,diesel fuel contains more oil than gasoline, so the blow-by gases aresignificantly oilier. Oily and sludgy blow-by gases are not onlynon-suitable for re-burn, they also tend to gum up the PCV valve 18making it impossible for the blow-by gases to be recycled at all. Thus,a blow-by filter 10 is necessary to clean the impurities out of theblow-by gases before they enter the PCV valve 18. The blow-by filter 10is also needed to return cleansed engine oil 56 back to the crankcase 20for further use.

The blow-by filter 10 is particularly illustrated in FIGS. 3-7. In FIG.3, the blow-by filter 10 is shown in a side view. The blow-by filter 10includes a canister 64 with a closed top portion 70 and a bottom portion72. The canister 64 can be made of metal, plastic, or any other materialor composite that is suitable for use in a high temperature, highpressure task. The closed top portion 70 of the canister 64 includes ablow-by intake port 66 and a fuel vapor exhaust port 68. The blow-byintake port 66 receives blow-by gases from the crankcase 20 of theengine 12 and passes the blow-by gases into the interior of the canister64. The fuel vapor exhaust port 68 vents purified blow-by gases from theinterior of the canister 64 to the PCV valve 18 (see FIG. 2) to bereturned to the engine 12. The closed top portion 70 of the canister 64is not removable from the canister 64.

The bottom portion 72 of the canister 64 includes a removable cover 74with clamps 76. The removable cover 74 includes an oil drainage port 78that allows for purified oil 56 (see FIG. 2) to drain back to thecrankcase 20 of the engine 12 (see FIG. 2). The blow-by intake port 66,fuel vapor exhaust port 68, and oil drainage port 78 are shown withvarious fittings in the preferred embodiment, but in other embodiments,these ports 66, 68, and 78 may include other fittings as necessary tocreate a proper connection with the appropriate engine parts. Theblow-by intake port 66, fuel vapor exhaust port 68, and oil drainageport 78 may or may not be made of the same material as the canister 64,but any material used to make these ports 66, 68, and 78 must be heatand pressure resistant.

FIG. 4 is taken from circle 4 of FIG. 3 and shows the closed top portion70 of the canister 64 in greater detail. The closed top portion 70 ofthe canister 64 may be molded as part of the canister 64, or may bepermanently attached to the canister 64 via some means such as welding.Likewise, the blow-by intake port 66 and fuel vapor exhaust port 68 arepermanently attached to the closed top portion 70 of the canister 64.FIG. 5 is taken from circle 5 of FIG. 3 and shows the bottom portion 72of the canister 64 in greater detail. The bottom portion 72 features aremovable cover 74 that is attached to the canister 64 with clamps 76.The removable cover 74 is configured to cover the open bottom portion 72of the canister 64. Two clamps 76 are shown in the preferred embodiment,but more clamps 76 may be included if necessary. The removable cover 74is fitted with an oil drainage port 78. The oil drainage port 78 allowsfor purified oil 56 (not shown) to drain back to the engine crankcase 20via the oil return line 80 (see FIG. 2). The oil drainage port 78 may beoffset from the center of the removable cover 74 in order to account forthe angle of the blow-by filter 10 as it is mounted under the hood 16 ofan automobile 14. The removable cover 74 allows for easy access to theinterior of the canister 64. This makes for easy cleaning andreplacement of the contents of the canister 64.

The blow-by filter 10 is shown in a cut-away side view in FIG. 6. Here,the filtering assembly 84 is shown in detail. The filtering assembly 84comprises multiple layers of metal mesh 86 of differing gauges. Theselayers of metal mesh 86 are loaded into the canister 64 through thecanister's open end 88. The layers of metal mesh 86 may be of the sametype of metal, or may be of different types of metal. The types of metalthat may be used include, but are not limited to: steel, stainlesssteel, aluminum, copper, brass, or bronze. In operation, unfilteredblow-by gases are received by the blow-by intake port 66 in the closedtop portion 70 of the canister 64. The blow-by gases begin to circulatethrough the layers of metal mesh 86 in the canister 64. Differentcontaminants and impurities are trapped at each layer of metal meshdepending on the gauge of the mesh and type of the metal. Largercontaminants are filtered by larger gauges of metal mesh 86. Smallercontaminants and impurities are filtered by the finer gauges of metalmesh 86. Likewise, some impurities may be trapped by certain types ofmetal. As the blow-by gases work through the filtering assembly 84,contaminants and impurities are trapped leaving two main bi-products:cleansed engine oil 56, and purified fuel vapor. The cleansed engine oil56 eventually collects in the bottom portion 72 of the canister 64 whereit drains via the oil drainage port 78 back to the crankcase 20 of theengine 12. The purified fuel vapor is vented through the fuel vaporexhaust port 68 in the closed top portion 70 of the canister 64 to passto the PCV valve 18 to be recycled through the intake manifold 22 of theengine 12. When the filtering assembly 84 requires periodic cleaning andmaintenance, it can be removed from the canister by un-latching theclamps 76 and removing the lid 74 from the bottom portion 72 of thecanister 64.

The open end 88 of the bottom portion 72 of the canister 64 is shown inFIG. 7, along with a gasket 90 and the removable cover 74. The gasket 90fits between the open end 88 of the canister 64 and the removable cover74. The gasket 90 is made of a compressible material that is heatresistant and impermeable to both air and liquid. Such a compressiblematerial may be plastic, rubber, or some other material with theseproperties. The purpose of including the gasket 90 at this position isto create a seal between the canister 64 and the removable like 74 thatprevents oil or other contaminants from leaking out. This may beessential because the contents of the canister 64 are under highpressure and temperatures. The gasket 90 may be removable for cleaningor replacement purposes.

Although a preferred embodiment of the invention has been described indetail for purposes of illustration, various modifications may be madeto each without departing from the scope and spirit of the invention.Accordingly, the invention is not to be limited, except as by theappended claims.

What is claimed is:
 1. A blow-by filter for an internal combustionengine, comprising: a canister having a closed top portion and an openbottom portion; a blow-by intake port and a fuel vapor exhaust portextending through the closed top portion of the canister; a removablecover attached to the open bottom portion of the canister; an oildrainage port extending through the removable cover; and a filteringassembly disposed within the canister, the filtering assembly comprisingmultiple layers of metal mesh having differing gauges.
 2. The blow-byfilter of claim 1, wherein the multiple layers of metal mesh comprisesteel, stainless steel, aluminum, copper, brass, or bronze.
 3. Theblow-by filter of claim 2, wherein the multiple layers of metal meshhaving differing gauges comprise one type of metal.
 4. The blow-byfilter of any of claims 1-3, further comprising a gasket between theremovable cover and the open bottom portion of the canister for sealingthe open bottom portion of the canister.
 5. The blow-by filter of claim4, wherein the gasket comprises a compressible material that is heatresistant and impermeable to both air and liquid.
 6. The blow-by filterof any of claims 1-3, further comprising clamps between the open bottomportion of the canister and the removable cover.
 7. A blow-by filter foran internal combustion engine, comprising: a canister having a closedtop portion and an open bottom portion; a blow-by intake port and a fuelvapor exhaust port extending through the closed top portion of thecanister; a removable cover attached to the open bottom portion andconfigured to cover and seal the open bottom portion; a gasket betweenthe removable cover and the open bottom portion of the canisterconfigured to seal the open bottom portion of the canister; clampsbetween the open bottom portion of the canister and the removable cover;an oil drainage port extending through the removable cover; and afiltering assembly disposed within the canister, the filtering assemblycomprising multiple layers of a combination of types of metal meshhaving differing gauges.
 8. The blow-by filter of claim 7, wherein thecanister is offset from the internal combustion engine.
 9. The blow-byfilter of claim 7, wherein the multiple layers of a combination of typesof metal mesh comprise steel, stainless steel, aluminum, copper, brass,or bronze.
 10. The blow-by filter of any of claims 7-9, wherein themultiple layers of a combination of types of metal mesh having differinggauges comprise a combination of types of metal.
 11. The blow-by filterof claim 10, wherein the gasket comprises a compressible material thatis heat resistant and impermeable to both air and liquid.